1. Technical Field
Disclosed are compositions and methods for use with cement. Specifically, disclosed are compositions and methods for controlling a downhole environment during cement operations.
2. Related Art
In many wellbores, cement can be used to form a layer between a casing and the formation. Delivery of additives to the cement can be problematic for a variety of reasons. First, the additives must be mixed with the cement slurry and delivered along with the slurry to the downhole location. Second, the additives must survive intact at the extreme downhole conditions in order to impart their additive properties. Third, controlling the release rate of an additive can be difficult in a downhole environment.
Encapsulation-based systems are of interest in the oil and gas industry in applications such as chemical additive preservation, small molecule release, particle delivery, and self-sealing materials. Many methods are used to encapsulate relevant chemical additives for the controlled release of contents. Example capsulation materials include polymeric coatings, inorganic shells, and mesoporous materials.
When placing cement in a wellbore, a multitude of additives (usually in large quantities) are considered and added to the slurry in order to meet a variety of functional needs suitable for diverse wellbore conditions. However, using large quantities of certain additives (for example, retarders and fluid loss control agents) may destabilize the slurry at the surface even before introducing the slurry into the wellbore.